The deployment comes as South Africa is coming to grips with its worst military setback since the end of apartheid in 1994. Thirteen of its troops were killed last month in a shootout with rebels in the neighbouring Central African Republic (CAR).
"The DRC deployment has nothing to do with the CAR. Neither did the CAR incident influence the decision to send the troops into the DRC. They are two different issues," Brigadier General Xolani Mabanga told Reuters on Sunday.
The size and timing of the deployment will depend on the terms set by the United Nations, he added.
The Security Council unanimously adopted in late March a resolution establishing the so-called intervention brigade as part of the existing 20 000-strong UN force in Congo, known as Monusco.
It is the first time the United Nations has created such a unit within a traditional peacekeeping force.
Congo's army is fighting M23 rebels in a conflict that has dragged Congo's east back into war and displaced more than half a million people.
The 13 soldiers killed in the Central African Republic were buried at the weekend as questions swirled over whether they had been sent to protect the financial interests of President Jacob Zuma's ruling ANC.
Zuma last week defended his decision to send them, saying they had died fighting for Pretoria's foreign policy, not his party's investments. – Reuters